Take eleven long-running panel studies from five countries — the United States, Germany, the Netherlands, Norway, Australia — pool every worker with repeated income and personality measurements, some tracked for twenty years across as many as eighteen waves, and run the whole thing through a continuous-time model built to catch effects wherever they actually peak, not just at whatever interval each original study happened to use. That’s the design behind Do Money and Time Change Who You Are? A Continuous Time Meta-Analysis and Review of Reciprocal Relationships Between Personality Traits and Income, published in Psychological Bulletin by Wen-Dong Li and Kaili Yu of The Chinese University of Hong Kong, with six co-authors, and covered Oct 20, 2026 by PsyPost. Pooled sample: up to 134,515 working adults. The finding: rising income predicts small later increases in conscientiousness and emotional stability, and small later decreases in agreeableness and extraversion. And it runs both ways — personality shifts predict later income too. Marcus Aurelius worried about exactly this, running a much bigger operation than a career. In Meditations 6.30, he told himself not to be “dyed” by the purple of command — not to let the office turn him into someone colder than the man who held it.

The Quick Verdict

Question	What we found
What was studied?	Whether rising income predicts later personality change, and whether personality change predicts later income, across working adults
Who ran it?	Wen-Dong Li and Kaili Yu (Chinese University of Hong Kong), with six co-authors
Where and when?	Psychological Bulletin, DOI 10.1037/bul0000526; covered Oct 20, 2026 by PsyPost
Sample	11 longitudinal panel studies, up to 134,515 workers, five Western countries, tracked 4-20 years
Core finding	Rising income predicted later increases in conscientiousness and emotional stability, and later decreases in agreeableness and extraversion
The other direction	Rising conscientiousness and emotional stability predicted later income gains; rising extraversion predicted smaller future income
What Marcus Aurelius already argued	In Meditations 6.30, he warned himself against being “dyed” by imperial power, urging himself to stay simple, kind, and unaffected by the office

The Quick Version

A 2026 meta-analysis of over 134,000 workers across five countries found that rising income tracks with small gains in discipline and emotional steadiness, and small losses in warmth and sociability — and that the relationship runs both ways, with personality shifts predicting later pay too. Marcus Aurelius named the mechanism, if not the regression coefficients, nineteen centuries earlier: status doesn’t just reveal character. It dyes it, and the color it leaves isn’t guaranteed to be a flattering one.

What the Study Actually Found

Most research in this area picks one arrow and tests it. Either personality predicts who earns more — the selection story — or circumstances reshape personality — the social-investment story — rarely both at once, in the same model. Li, Yu, and their co-authors built something that could catch both arrows moving simultaneously, pooling eleven large panel datasets, some running two decades deep with up to eighteen separate measurement waves, into a single continuous-time analysis. That technique matters here specifically because income and personality don’t move in lockstep with however many years happened to separate one survey wave from the next. The team’s model placed the strongest income-to-personality effects at roughly a year to a year and a half after a change in pay — a window a study with two or three widely spaced waves would likely miss outright.

The headline numbers are modest, and the researchers don’t dress them up as anything else. A one-standard-deviation rise in income predicted about a 0.06-standard-deviation rise in conscientiousness — real, but not dramatic. Emotional stability moved the same direction at roughly half that size. Agreeableness and extraversion moved the other way, smaller still, around 0.01. Li told PsyPost that “increases in income may reduce your agreeableness (being nice to others), and extraversion.” The reverse arrow held a genuine surprise: rising extraversion predicted smaller future income, not larger. “Increases in extraversion, contrary to our expectations, were related to decreases in income,” Li said. Conscientiousness and emotional stability, by contrast, ran a loop that reinforced itself in both directions — gains in either trait predicted later income gains, and income gains predicted further trait gains.

The paper frames the finding as a quiet referee match between two older theories of what personality even is. The Five Factor Model, dominant since the 1990s, treats traits as largely settled by early adulthood — life events might sort people into certain jobs, but the job isn’t supposed to have much power to reshape the person who holds it. The Neo-Socioanalytic Model argues the opposite: a demanding role requires habitual behavioral adjustments — more discipline because the work punishes sloppiness, less patience for agreeableness because a competitive role rewards a sharper edge — and those adjustments, repeated long enough, stop being an act and become who someone is. The “social investment principle” is the specific claim buried inside that model: invest in a role’s particular demands for long enough, and the role invests back in you. Permanently.

What Did Marcus Aurelius Mean By This?

Meditations 6.30, written while Marcus Aurelius governed an empire from a military campaign on the northern frontier, warns himself directly: “Take care that thou art not made into a Caesar, that thou art not dyed with this dye; for such things happen.” He follows the warning with the alternative he’s trying to hold onto — stay “simple, good, pure, serious, free from affectation, a friend of justice, a worshipper of the gods, kind, affectionate, strenuous in all proper acts.”

The word doing the real work is “dyed.” Marcus isn’t warning himself against one corrupt decision, the kind you could catch and reverse. Dye doesn’t sit on the surface of cloth — it gets absorbed into the fiber, and the fabric that comes out the other end is a different color all the way through, not stained in one spot. That’s a theory of gradual, structural change close to identical to what the Neo-Socioanalytic Model describes with research-grade vocabulary nineteen centuries later: not one dramatic corruption, but accumulated small adjustments to a role’s daily demands, compounding until the person holding the office and the person who started holding it aren’t quite the same person.

Line up his list against the study’s five traits and the overlap is almost suspicious. The qualities Marcus names as being at risk — kind, affectionate, simple — map onto agreeableness and extraversion, the two traits the 2026 data found eroding as income climbs. The qualities he insists on keeping regardless — serious, a friend of justice, strenuous in all proper acts — map onto conscientiousness, the trait the data found strengthening. He wasn’t worried about becoming lazy in office. He was worried about becoming efficient and cold in the exact same stroke, which is close to the precise shape Li and Yu’s regression table just drew, run through a different vocabulary entirely.

Why Does Income Pull Personality in Two Directions at Once?

1. Higher-paying roles reward follow-through and composure, which is a daily drill in exactly the traits the study found increasing. A job that punishes missed deadlines and rewards staying level under pressure is functionally training conscientiousness and emotional stability, whether or not anyone involved thinks of it that way.
2. The same roles often reward a sharper, less accommodating edge, which is a daily drill against agreeableness. Negotiating, managing people, protecting turf — these reward someone willing to say no more often, not someone who’s easy to get along with.
3. Rising status reduces the social need to charm people, which may explain the drop in extraversion. Lower-income work often depends on staying likable to people who hold power over you day to day. Higher income can mean needing fewer people’s approval, and the daily muscle of performing warmth gets less use when it’s no longer required for survival.
4. The reverse arrow — personality shaping income — fits the Five Factor Model’s story for two traits and breaks it for one. Employers reward conscientiousness and emotional stability directly, which fits the selection account fine. But rising extraversion predicting smaller future income was the one finding the researchers didn’t see coming, and the paper doesn’t offer a settled explanation for it yet.

Why the Study and the Philosophy Rhyme

The honest version of this isn’t “a Roman emperor predicted a 2026 psychology meta-analysis.” It’s narrower, and it holds up better for being narrower: Marcus’s specific claim was that holding power reshapes character gradually and specifically, eroding warmth while reinforcing discipline, not that power corrupts in some generic, moralizing sense. Li and Yu weren’t testing Stoic philosophy. They were testing whether income and the Big Five move together over time across eleven unrelated datasets. But the specific shape of what moved — up on the traits a role demands, down on the traits a role doesn’t need — lines up with the specific shape of what a man running the Roman Empire was afraid would happen to him, named almost two thousand years before anyone had a word for “agreeableness.”

It connects to the West Point research on conscientiousness and leadership covered here through Heraclitus — that study found conscientiousness, not IQ, was the strongest predictor of who becomes a good leader, the same trait this study found income reinforcing, approached from the opposite direction. It sits close to the lottery-windfall research on marriage covered through Boethius: both studies track how a sudden or gradual change in financial circumstance reshapes something assumed to be stable — there a marriage, here a personality — and both find the wheel turns differently depending on which trait, or which spouse, you’re asking about. And it rhymes with the strategic-kindness research covered through La Rochefoucauld: that study found competitive niceness tracking Machiavellianism rather than real warmth, a reminder that agreeableness itself can be a performance tuned to incentives — which is close to what this study implies happens when the incentives shift toward needing less of it.

The Gap Marcus Didn’t See Coming

Here’s where the comparison is more interesting than a clean match.

Marcus was describing a single office, held by one person, at the furthest extreme of status — an emperor, not a mid-career worker who got a raise. His worry was personal and examined: a specific conscience asking whether today’s decisions were corroding him. The study measures something far more diffuse — the average, statistically detectable drift of over a hundred thousand ordinary workers’ personality scores, nobody individually diagnosed, nobody necessarily aware it’s happening at all. Marcus had the advantage, if it is one, of being able to watch for the dye in himself, in writing, daily. Most of the workers in this dataset have no particular reason to suspect their last promotion nudged their agreeableness down a fraction of a standard deviation.

The size of the effect is also a real gap, not just a difference in scale. Marcus wrote as though the corruption of power was close to inevitable — “such things happen,” he says, almost resigned to it. The 2026 numbers are genuinely small: a 0.06 standard-deviation shift in conscientiousness per standard-deviation shift in income is detectable across 134,515 people with a decade of data behind them, but it would be invisible inside any one life, including Marcus’s own, had anyone been tracking him with a personality inventory instead of a journal.

What This Study Doesn’t Show

Be precise about the size of this. The framing invites more confidence than the data earns.

Observational, Not Experimental

The design tracks income and personality moving together over years of real careers. Nobody was randomly assigned a raise. The researchers can’t rule out a third factor — a new relationship, a health change, an unmeasured life event riding alongside the pay change — driving both the income shift and the personality shift at once.

Five Wealthy, Western Countries

The eleven studies draw from the United States, Germany, the Netherlands, Norway, and Australia — high-income, Western labor markets with broadly similar social safety nets. Whether the same pattern holds in economies with different job security, inequality, or social structure is untested.

Self-Reported Personality

Every trait score in the meta-analysis comes from people describing themselves, not from peer or supervisor ratings. A person’s sense of their own agreeableness and extraversion can shift even when someone watching them from outside would score them identically.

The Effects Are Real but Small

A 0.06-standard-deviation shift is a genuine, replicated finding pooled across eleven studies, not a dramatic transformation. Most people who get a raise will not notice themselves becoming a different person. The pattern is statistically real and personally subtle, both at once.

What Actually Follows From This

1. A raise is not morally neutral for who you become, even though nobody hands you a warning label with the paycheck. The traits that make someone easier to work with and easier to love — warmth, sociability — are, on average, the ones a bigger income quietly taxes.
2. The traits getting reinforced aren’t the villain here — conscientiousness and emotional stability improving is good news by almost any measure. Marcus’s own list makes the same split: he wasn’t trying to stay lazy, he was trying to stay kind while also staying disciplined, and the data says those two goals pull apart as status rises.
3. Marcus’s actual practice, not just his diagnosis, is the useful part. He didn’t trust willpower to catch the dye once it had already set. He wrote the reminder down before the day’s business, naming the specific trait he was afraid of losing. If a role is reshaping you in a predictable direction, noticing it before year ten is the point where a journal entry or an honest conversation with someone outside the role still has a chance to matter.

Marcus Aurelius never ran a regression, and Li, Yu, and their six co-authors weren’t trying to vindicate Stoicism. But a continuous-time model built to catch which trait moves after which raise landed close to the exact asymmetry an emperor warned himself about from a tent on the Danube: status doesn’t erase character. It edits it, line by line, in the direction the role needs — more discipline, less warmth — whether or not anyone wearing the purple notices the dye taking.

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This post discusses a 2026 meta-analysis published in Psychological Bulletin (Li, Yu, and colleagues, DOI: 10.1037/bul0000526), reported by PsyPost, and Marcus Aurelius’s Meditations, Book 6. The study is observational, drawn from eleven panel datasets in five Western countries, and cannot establish that income causes personality change rather than reflecting unmeasured life circumstances that accompany both.